Fossil fuels are presently being used in tremendous quantities in this country and it is said that such fuels, particularly oil and natural gas, may be depleted by the beginning of the 21st century, while there may be sufficient coal to last for an additional one hundred or so years. Power from nuclear fission is relatively expensive because of initial outlays for power plant manufacture, and difficulties arise in handling the waste products from this source of power. Power production from nuclear fission may not be produced for many years, if ever. The generation of power from solar energy has recently stirred a great deal of interest, but presently, solar power is feasible only in small units, such as for an individual home, and solar power producing units are extremely expensive to install relative to the amount of useful power obtained; additionally solar power is less useful in northern climates.
British Pat. No. 29,690 to Aynton discloses engines which are operated by the dissolution of gasses, such as ammonia, in solvents, such as water. While the Aynton engine system operates cyclically, part of the cyclical path is open to the atmosphere. Thus, while the system operates in a cycle, or loop, the loop is not a "closed loop" as is the system described hereinbelow. Furthermore, because the Aynton loop is open to the atmosphere, the pressure differentials therein are between atmospheric pressure and below, or a partial vacuum. Thus, the pressure drops obtained in Aynton's system can at most be one atmosphere. Additionally, in the Aynton system, the gaseous ammonia inlet to the dissolving chamber is placed above the water. In that configuration, the water becomes saturated with ammonia near its surface thereby becoming unable to accept more ammonia and causing a back pressure to build up into the engine until such back pressure equals that of the pressure source, thereby stopping the engine.
Another British patent, No. 294,882 to the International General Electric Company, Incorporated, also teaches an engine which is run by a gas, such as ammonia, which is dissolved in a solvent, such as water. In this patent, both the inlet for fresh water and the outlet for solution to be separated are located near the bottom of the ammonia-water mixing tank. Ammonia gas addition occurs above the surface of the liquid in the mixer, thereby causing a solvent saturation problem as discussed above for the Aynton system. With the gas and liquid inlet and outlet configurations as taught therein, the liquids coming into and going out from the mixing or dissolving chamber have approximately the same ammonia content and the incoming ammonia does not mix directly with the freshly separated solvent. Additionally, the solution richest in ammonia, enters the separating boiler near the bottom thereof, a region which is otherwise poorest in ammonia, while the solvent to be recirculated for resolution with ammonia, comes from the upper portion of the boiler which is the portion richest in ammonia.
U.S. Pat. No. 3,945,211 to Rowe and entitled "Vacuum Engine" describes a power generating system in which power to run an engine is derived from a vacuum created by the dissolution of ammonia in water. Rowe's system comprises an engine having at least one variable volume chamber in which a vacuum is developed, or alternatively the vacuum may be developed at a tank remote from the variable volume engine of his system. (As used in Rowe "vacuum" is understood to be a pressure below atmospheric pressure). In its principal embodiment, the Rowe system is a "one path" system, that is, the water and ammonia are mixed to generate power and then must be retained, collected and either recycled remote from the power producing engine or used in some other process. In addition, he discloses the use of a "small conversion plant" which may be established adjacent to the engine wherein the water and ammonia gas may be regenerated.
There are several disadvantages to the Rowe "Vacuum Engine". One of these disadvantages is that the system must work with one portion being under vacuum, which limits the available pressure differential running the engine to one atmosphere. Use of vacuum also results in having to use costly sealing techniques to insure that there are no leaks in the system which will allow the internal pressure to come to atmospheric and thereby stop the engine. A second disadvantage is that the system is limited to the use of a variable volume engine, thereby limiting the generality of its use. Another disadvantage of the Rowe system is that in embodiments where the water and ammonia are not mixed within the variable volume engine, but rather in a separate solution tank at a location remote from the engine, the engine exhaust manifold must communicate with the solution tank such that the exit from the manifold is below the level of the liquid in the solution tank thereby lessening the effect of dissolution of the ammonia gas with the dissolving liquid because the incoming gas is dissolved in a solution already containing relatively large amounts of the gas. Yet another disadvantage in the Rowe system is that there is no account taken of the heat of solution generated when ammonia gas is dissolved in water. In certain of the Rowe embodiments this heat of solution could cause a back pressure buildup and eventually shut down the engine.